Novel polymorphisms in TICAM2 and NOD1 associated with tuberculosis progression phenotypes in Ethiopian populations

Abstract

BackgroundInfection by Mycobacterium tuberculosis (Mtb) is a necessary but not sufficient cause for tuberculosis (TB). Although numerous studies suggest human genetic variation may influence TB pathogenesis, there is a conspicuous lack of replication, likely due to imprecise phenotype definition. We aimed to replicate novel findings from a Ugandan cohort in Ethiopian populations.MethodWe ascertained TB cases and household controls (n = 292) from three different ethnic groups. Latent Mtb infection was determined using Quantiferon to develop reliable TB progression phenotypes. We sequenced exonic regions of TICAM2 and NOD1.ResultSignificant novel associations were observed between two variants in NOD1 and TB: rs751770147 [unadjusted p = 7.28 × 10−5] and chr7:30477156(T), a novel variant, [unadjusted p = 1.04 × 10−4]. Two SNPs in TICAM2 were nominally associated with TB, including rs2288384 [unadjusted p = 0.003]. Haplotype-based association tests supported the SNP-based results.ConclusionWe replicated the association of TICAM2 and NOD1 with TB and identified novel genetic associations with TB in Ethiopian populations.